The present invention relates to a rolling bonding method for different kinds of metals and the apparatus therefor, especially, to a liquid-solid rolling bonding method for different kinds of metals and the apparatus therefor.
Clad metal sheet is a kind of new material formed by integrating two or more heterogeneous metals under the function of high temperature and high pressure. According to the requirements of the design, it can fully combine the advantages of each of the components. It also has many other advantages, such as low cost and high combination property, good mechanical, physical and chemical engineering properties including high strength, abrasive resistance, corrosion resistance etc. So it is widely used in architecture and mechanical industries, for making cookers and tableware, furniture, chemical industry decoration, automobile industry space flight, aviation etc.
The methods for making clad metal sheets are divided into five kinds: rolling bonding method, powder rolling method, explosion bonding method, clad casting method and spraying plating method.
Rolling bonding method, which is divided into hot rolling bonding method and cold rolling bonding method as disclosed by U.S. Pat. No. 3,545,943, is the most widely adopted method for making clad metal sheets. The realization of the method depends on the physical contact of new surfaces arising from the extension during rolling, so the reduction percentage at the first step must be high enough (ordinarily more than 50%). The method needs a huge rolling mill to generate a great rolling force and it also relies on annealing which follows the rolling process to realize metallurgical bonding. However, the bonding strength is still low. In recent years, there are some developments in this field. For example, continuous rolling bonding, asynchronous rolling bonding, differential temperature rolling bonding have been developed. However, the problems such as great investment of apparatus, high dissipation of energy and high cost have not been solved completely.
JPJ8667705A (1984), JAJ54124804 (1981) and JAJ8021518 (1984) and U.S. Pat. No. 4,308,321 (1981) disclose a powder rolling bonding method for heterogeneous metals. The method is to scatter a metal powder onto a solid metal and to sinter them under a protective atmosphere, then to roll them to form a clad metal sheet. This method has the shortcomings of complex procedures, long flow path and high consumption of energy. This method is only suitable for making some special clad metal sheets, such as the bearing clad strip made of copper-lead alloy and steel.
Bradgessky (Please refer to xe2x80x9cExplosion Meld Forming And Compressionxe2x80x9d written by Bradgessky and translated by Fule Li, Mechanical Industry Press, 1988, P78) disclosed an explosion bonding method. The method is to utilize jet flows arising from the explosion to clean the surface and to utilize the impact force and instantaneous high temperature arising from the explosion to realize bonding. The method is simple and economical. However, it is only suitable for making thick clad metal sheets. Moreover, it has high demands on production site and the production can not be continuously.
U.S. Pat. No. 3,495,649 (1970) disclosed a clad casting method. This method is to cast a molten metal on the surface of a solid base material to realize metallurgical bonding. This method is relatively simple and it can be used to produce work-blanks and components. However, the surface of the base metal is ready to be oxidized, thus it is necessary to treat the work-blanks before they are processed to form the final product. Furthermore, the final product has strong interface residual stress and does not have enough bonding strength. Moreover, the cost of the method is high.
U.S. Pat. No. 4,333,775 (1982), GB159861 (1977), JAJ8019522 (1978) and DT2928317 (1978) disclosed a spraying plating method. This method is to spray a hot molten metal alloy onto a solid steel plate by using a spray lance. The advantage of this method is that there is no segregation in the components of the alloy due to the rapid cooling procedure during spraying. Since the molten metal is ready to be oxidized when being sprayed, the final metal has low bonding strength. Moreover, the apparatus of the method is complicated and the investment is relatively high.
Therefore, the key to the development of clad metal is to look for a more economical and efficient manufacturing method with more simple procedures.
One object of the present invention is to provide a liquid-solid rolling bonding method for different kinds of metals to overcome the disadvantages of the prior art and to produce a clad metal sheet with high bonding strength, simple procedures and high economic efficiency.
Another object of the present invention is to provide an apparatus for carrying out the above-mentioned a liquid-solid rolling bonding method for different kinds of metals.
The present invention discloses a liquid-solid rolling bonding method for different kinds of metals and an apparatus to carry out the method of the present invention. The method of the present invention comprises the following steps: pouring a molten (liquid) metal onto the surface of a heterogeneous solid base metal coated with a soldering flux, and rolling these two metals under pressure to make the molten metal solidified and bond to the surface of the solid base metal under rapid cooling. Thus, the method of the present invention realizes the metallurgical bonding of two or more metals.
The present invention also discloses an apparatus for carrying out the method of the present invention. The apparatus for carrying out the method invention comprises an unwinding machine, a soldering flux tank, a heating-drying apparatus, a pouring nozzle, an interior water-cooling roller and a roll-collecting machine arranged in order. A pouring basket is disposed above the pouring nozzle and a base frame is disposed below the pouring nozzle.